1. Field of the Invention
The present invention relates to systems and methods for selecting advertisements for placement on web pages, including but not limited to web pages used by a web search engine to deliver search results to a user.
2. Background
Addressing the information needs of users has been one of the main goals of web search engines since their early days. Web search engines can provide fast and accurate results to user queries, usually free of charge. However, in order to provide this searching service free of charge, search engine providers need to offer advertising opportunities that finance their operating costs. To this end, Web search engines and/or advertisement (ad) serving systems associated therewith may serve users a variety of different ad types, include banner ads, pop-up ads, and sponsored search ads, among others. These ads may be provided to users at various times and can be placed at various locations on a web page delivered to a user by the web search engine. Web search engine providers are often paid by the providers of the advertisements per user selection of each advertisement, e.g., per user click. Therefore, it is beneficial for the web search engine providers to maximize the interaction with, and thus the profit obtained from, each advertisement shown to the user.
Sponsored search ads are ads that are served on web pages used to deliver search results to a user in response to a user query and that relate in some manner to the user query. Since the spatial requirements needed to display all the search results corresponding to a given user query can exceed a single web page, a web search engine may deliver search results across a series of web search results pages that can be consecutively accessed by a user. For example, a user may receive a first web search results page in a series of web search results pages and then click on a “next” button to access a subsequent page in the series. Some web search engines deliver sponsored search ads across each web search results page in the series. In particular, a conventional approach to serving such sponsored search ads involves ranking all candidate ads based on a likelihood of each ad being selected by the user, and then placing a highest-ranking set of candidate ads on a first web search results page when accessed by the user, a next highest-ranking set of candidate ads on a second web search results page when accessed by the user, and so forth. It would be beneficial if the techniques used to select sponsored search ads for placement on each web search results page in a series of consecutively-accessed web search results pages could be improved in order to maximize user selection of such ads. By improving these techniques, users may be provided with improved access to more relevant sponsored search ads and the sponsored search ad revenue accruing to a web search engine provider may be increased.